Radio frequency for satellite communication ranges approximately from 1 GHz to 40 GHz, as shown in FIG. 13. Normally, C and Ku bands are used for digital TV transmission and Ka band for high-speed internet access. This is due to the fact that attenuation caused by rain or other environmental factors increases with frequency, thus Ka band is more sensitive to the weather and other factors. As C and Ku bands become increasingly depleted and/or congested, communication using Ka band, including satellite communication for digital TV transmission and very small aperture terminal (VSAT) networking, is under rigorous development. Comparing to C and Ku bands, Ka band (including K band) provides much wider frequency range for use, extending from approximately 18 to 40 GHz.
However, existing antenna systems for receiving and converting signals from a satellite are designed and tuned in accordance with the specific radio frequency (RF) spectrum of the targeted satellite. As such, an antenna system configured for use with one spectrum will not work properly with another spectrum. For example, an antenna system configured for use with C band or Ku band cannot be used in Ka band, or vice verse. In order to receive and/or convert signals from another satellite in a different RF spectrum , the entire antenna system has to be replaced by another antenna system specifically configured for the newly desired spectrum. Replacement of an entire system is expensive, sometime may not be affordable, as an antenna system and particularly a maritime antenna system typically costs tens of thousands dollars.
Alternatively, a system having multi-antennas in a single radome has been developed to communicate in multiple RF spectrums. The multi-antenna system basically configures each of the antennas in accordance with one of the targeted satellites. An exemplar of such multi-antenna systems can be found in U.S. Patent Application Publication No. 2009/0009416 to Blalock.
Although it can receive signals in two or more RF spectrums, a multi-antenna system has several disadvantages. It is generally larger and requires a significant mounting space and/or a larger footprint, which may not available under certain circumstances. It is heavier and thus place considerable challenges on positioning and stabilizing a system since an antenna system has to be continuously and accurately directed towards the targeted satellite in order to function properly. In addition, it is more expensive than a single antenna system.
In light of the foregoing, it would be useful to provide an antenna system and method using the same, which overcome the above and other disadvantages.